Atom's papercraft locomotive engine doesn't actually run on steam (you have to push it to make it go), but man, it sure does go. Link (via Neatorama)
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.